Gender ratio aged over 60:
Amount of women per every 100 males that are over the age of 60 in each country. For instance, in Russia, for every 100 males over 60, there are 196 females who are over 60.

Gender ratio aged over 65:
Amount of women per every 100 males that are over the age of 65 in each country. For instance, in Russia, for every 100 males over 65, there are 210.6 females who are over 65.

Gender ratio aged over 80:
Amount of women per every 100 males that are over the age of 80 in each country. For instance, in North Korea, for every 100 males over 80, there are 411.8 females who are over 80.

Global Gender Gap Index:
The Gender Gap Index considers gender inequality in the dimensions of economic participation (equality of salaries, labor market participation and access to high-skilled employment); access to education; political participation; and health (life expectancy and sex ratio). The highest score of 1 means total equality, 0 means complete inequality. The Index is calculated by the World Economic Forum.